1. Field
Example embodiments relate to methods of inspecting structures, and more particularly, to methods of optically inspecting layer or pattern structures.
2. Description of Related Art
With an increase in the degree of integration of semiconductor devices the critical dimensions of structures may be reduced to tens of nanometers (nm). The critical dimensions of the structures may be measured by optical critical dimension (OCD) measurement. In OCD measurement, an approximate model may be formed and various intervening variables may be continuously changed to cancel differences in measurement between the model and structures to be inspected. In this process, a complex tool referred to as rigorous coupled wave analysis (RCWA) may be required. Conventional OCD measurement may be problematic in that a model must be approximately formed and it is difficult to cancel a difference in measurement between the model and measurement structures.